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            <div><h3 class="title">
                <a name="asio.reference.IoObjectService"></a><a class="link" href="IoObjectService.html"
                                                                title="I/O object service requirements">I/O object
                service requirements</a>
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    <p>
        An I/O object service must meet the requirements for a <a class="link" href="Service.html"
                                                                  title="Service requirements">service</a>,
        as well as the requirements listed below.
    </p>
    <p>
        In the table below, <code class="computeroutput"><span class="identifier">X</span></code> denotes
        an I/O object service class, <code class="computeroutput"><span class="identifier">a</span></code>
        and <code class="computeroutput"><span class="identifier">ao</span></code> denote values of type
        <code class="computeroutput"><span class="identifier">X</span></code>, <code class="computeroutput"><span
            class="identifier">b</span></code>
        and <code class="computeroutput"><span class="identifier">c</span></code> denote values of type
        <code class="computeroutput"><span class="identifier">X</span><span class="special">::</span><span
                class="identifier">implementation_type</span></code>, and <code class="computeroutput"><span
            class="identifier">u</span></code> denotes an identifier.
    </p>
    <div class="table">
        <a name="asio.reference.IoObjectService.t0"></a>
        <p class="title"><b>Table 23. IoObjectService requirements</b></p>
        <div class="table-contents">
            <table class="table" summary="IoObjectService requirements">
                <colgroup>
                    <col>
                    <col>
                    <col>
                </colgroup>
                <thead>
                <tr>
                    <th>
                        <p>
                            expression
                        </p>
                    </th>
                    <th>
                        <p>
                            return type
                        </p>
                    </th>
                    <th>
                        <p>
                            assertion/note<br> pre/post-condition
                        </p>
                    </th>
                </tr>
                </thead>
                <tbody>
                <tr>
                    <td>
                        <p>
                            <code class="computeroutput"><span class="identifier">X</span><span
                                    class="special">::</span><span class="identifier">implementation_type</span></code>
                        </p>
                    </td>
                    <td>
                    </td>
                    <td>
                    </td>
                </tr>
                <tr>
                    <td>
                        <p>
                            <code class="computeroutput"><span class="identifier">X</span><span
                                    class="special">::</span><span class="identifier">implementation_type</span> <span
                                    class="identifier">u</span><span class="special">;</span></code>
                        </p>
                    </td>
                    <td>
                    </td>
                    <td>
                        <p>
                            note: <code class="computeroutput"><span class="identifier">X</span><span
                                class="special">::</span><span class="identifier">implementation_type</span></code> has
                            a public
                            default constructor and destructor.
                        </p>
                    </td>
                </tr>
                <tr>
                    <td>
<pre class="programlisting"><span class="identifier">a</span><span class="special">.</span><span class="identifier">construct</span><span
        class="special">(</span><span class="identifier">b</span><span class="special">);</span>
</pre>
                    </td>
                    <td>
                    </td>
                    <td>
                    </td>
                </tr>
                <tr>
                    <td>
<pre class="programlisting"><span class="identifier">a</span><span class="special">.</span><span class="identifier">destroy</span><span
        class="special">(</span><span class="identifier">b</span><span class="special">);</span>
</pre>
                    </td>
                    <td>
                    </td>
                    <td>
                        <p>
                            note: <code class="computeroutput"><span class="identifier">destroy</span><span
                                class="special">()</span></code>
                            will only be called on a value that has previously been initialised
                            with <code class="computeroutput"><span class="identifier">construct</span><span
                                class="special">()</span></code> or <code class="computeroutput"><span
                                class="identifier">move_construct</span><span class="special">()</span></code>.
                        </p>
                    </td>
                </tr>
                <tr>
                    <td>
<pre class="programlisting"><span class="identifier">a</span><span class="special">.</span><span class="identifier">move_construct</span><span
        class="special">(</span><span class="identifier">b</span><span class="special">,</span> <span
        class="identifier">c</span><span class="special">);</span>
</pre>
                    </td>
                    <td>
                    </td>
                    <td>
                        <p>
                            note: only required for I/O objects that support movability.
                        </p>
                    </td>
                </tr>
                <tr>
                    <td>
<pre class="programlisting"><span class="identifier">a</span><span class="special">.</span><span class="identifier">move_assign</span><span
        class="special">(</span><span class="identifier">b</span><span class="special">,</span> <span
        class="identifier">ao</span><span class="special">,</span> <span class="identifier">c</span><span
        class="special">);</span>
</pre>
                    </td>
                    <td>
                    </td>
                    <td>
                        <p>
                            note: only required for I/O objects that support movability.
                        </p>
                    </td>
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                </tbody>
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